Target "Operating Costs"

Comments

GOAL: Estimate monthly operating costs for a calorie fountain, including power, water, and nutrients, but not including cost of initial construction.

Explanation

Calorie fountains will only be viable if they cost significantly less to operate than the grocery budget they're trying to replace.

Deliverables

  • a sketch of low income family spending patterns
  • a list of all recurring costs to run a calorie fountain
  • a monthly operating budget for a calorie fountain

Success conditions

  • the operating budget is less than the amount typically spent on groceries by a low-income family

Progress

  • 2023-03-26: sketched power consumption costs
  • 2023-03-26: sketched family food budgets
  • 2023-03-26: sketched water costs
  • 2023-03-26: sketched nutrient costs

Research Notes

Target budget

  • gather credible spending pattern data to determine whether the sketched costs are acceptable
  • Canadian Market Basket Measure stats
  • reference family = 2 adults, 1 child, 1 teen
  • = approx 3.5 adults in terms of calories reqd
  • in 2021 spent appx $13k on food
    • average household across the country
    • not specifically low-income
  • = appx $310/adult

Power Cost Sketch

  • assume 300 sqft of salsify, in Kratky tubs
  • as per here, estimate 20-40W of LED lighting power per sqft (older technologies required higher power levels)
  • we're lighting 300 sqft
  • crops need appx 2500 lumens/sqft
  • assuming 12/12 daytime/nighttime cycle
  • that's 30W x 300sqft x 12hr/day x 30days
  • = 3.24M Wh per month
  • @ 14¢/kWh = $450 / month / person

  • or $225-300 at 6-8 hours of light

  • [x] Repeat calculations for FECiDA light specifically ✔

    • can't confirm reliably, but anecdotal claims are 12000 lumens with 130W power draw at full brightness
    • = 4.8 sqft coverage
    • = 62.5 units to cover 300 sqft
      • capital cost 63x$99 = $6237
    • = 62.5 x 130 = 8125W draw
    • x 12 hrs x 30 days = 2925 kWh @ 14¢
    • = $409.50 / month for our
    • or $205-275 at 6-8 hours lighting

  • [x] Repeat calculations for T5 light specifically ✔

    • 20000 lumens
    • = 8 sqft coverage
    • = 37.5 units required to cover 300 sqft
      • capital cost 38 x @175 = $6650
    • = 38 x 230W = 8740W
    • x 12 hrs x 30 days = 3147 kWh @ 14¢
    • = $440 / month
    • or $220-295

  • [x] Dig deeper to verify that 30W estimate applies to LED lights

    • full sun = appx 5750K lighting (+/- 750) @ 2500 lum/sqft (+/- 500)
    • shift lower for seedlings (4500-5000K)
    • yes, after sketching costs for several lights based on lumens rather than watts, the results are comparable with the original sketch

  • but according to this, salsify only needs 6-8 hours of light per day

    • if true, that's 50-67% of expected power draw
    • which brings calorie fountain power consumption costs significantly below the grocery budget
    • 5%-33% cheaper

Water Cost Sketch

  • assume Kratky method
  • as per here, roots grow to 12” long, so need 14” deep tubs filled 13” deep at start of every 4 month cycle
  • = 300 sqft x 1.083' = 325 cubft water
  • = $22.50 in Saskatoon
  • = $5.63/month
  • average price for water $53 for 883 cubft as per here
  • = $19.51 for 325 cubft
  • = $4.88/m
  • estimate water costs at $5/month

Nutrient Cost Sketch

For sketching purposes, I'm going to assume a standard commercial fertilizer at a standard concentration, as described here - Masterblend 2g, Epsom 1g, CalNite 2g, water 1gal - cost of water has already been sketched - 12.5 kg kit has 5000/2500/5000g for $146 - enough for 2500 gal - 325 cubft water = 2431 gal - = $142 for 4 months - = $35.50/month

Findings

  • families spend appx $310/per/m for food
  • fountain operations: $250+5+35 = $290/per/m
  • surprised that off the shelf supplies and equip already has the fountain cheaper than groceries
  • still expect to be able to reduce these costs substantially

Declaring target has been met.

Further research

Comments